JPH06326621A - Tuning method for wireless microphone - Google Patents

Abstract

PURPOSE:To automatically select a clear channel in which an outside noise or interference or the like can be reduced. CONSTITUTION:When a noise level is beyond a reference level in an arbitrary channel, a CPU 17 at a receiver side operates a scan operation to the entire channels, selects the channel in which the noise level is the minimum, transmits the selected channel data through an infrared ray to a wireless microphone side, and turns a transmission channel at the wireless microphone side to a reception channel at the receiver side. Even when the outside noise or the interference or the like is generated in the channel which is being used at present, it is not necessary to operate a frequency selection switch 18 at the receiver side, and to select the channel in which the outside noise or the interference or the like is reduced, and simultaneously it is not necessary to operate a frequency selection switch at the wireless microphone side, and to select the transmission channel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of selecting a wireless microphone for automatically selecting an appropriate channel in a wireless microphone having a plurality of channels.

[0002]

2. Description of the Related Art Conventionally, in a wireless microphone system including a combination of a wireless microphone and a receiver, when external noise or interference occurs, the channel is changed to a channel with less external noise or interference. .

In this case, the receiving channel is first changed by selecting a channel having less external noise and interference on the receiver side, and the transmitting channel on the wireless microphone side is matched with the selected receiving channel.

That is, FIG. 1 shows an example of the structure of a wireless microphone. When a voice signal taken in from a microphone 1 is amplified by an amplifier 2, it is modulated by a transmission frequency corresponding to a transmission channel by a VCO 3, Further, after being amplified by the high frequency amplifier 4, it is transmitted from the antenna 5. The oscillation frequency corresponding to the transmission channel in the PLL circuit is set by the CPU 7 supplying control data to the PLL 6 according to the selection of the frequency selection switch 8.

The structure of the receiver for receiving the high frequency signal transmitted from the wireless microphone is, for example, as shown in FIG. 2, and the high frequency signal taken in from the antenna 10 is amplified by the high frequency amplifier 11, passes through the mixer 12, and then, When the intermediate frequency is amplified by the intermediate amplifier 13, it is detected by the detector 14 and demodulated. A local oscillator 15 and a PLL 16 are connected to the mixer 12.
The set frequency corresponding to the reception channel from the PLL circuit composed of is obtained by mixing the high frequency output from the high frequency amplifier 11 and the oscillation frequency from the local oscillator 15 with an intermediate frequency (10.7 MH).
Z) is obtained. The CPU 17 outputs control data to the PLL 16 in response to the selection of the frequency selection switch 18.

[0006]

However, in the wireless microphone system including the above-described conventional combination of the wireless microphone and the receiver, in order to avoid the occurrence of external noise and interference, channels with less external noise and interference are generated. Therefore, it is necessary to first operate the frequency selection switch 18 on the receiver side to select a receiving channel with less external noise and interference, which causes a problem that the channel selecting operation is complicated. It was

Also, it is necessary to match the transmission channel on the wireless microphone side with the clear reception channel with less external noise and interference selected on the receiver side.
After all, there was a problem that the channel selection operation was complicated.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method of selecting a wireless microphone capable of automatically performing a channel selecting operation.

[0009]

In order to achieve the above object, the present invention is a method of selecting a channel between a wireless microphone and a receiver, wherein a noise level for each channel is It is characterized in that it is detected and a specific channel is selected according to the magnitude of the detected noise level.

[0010]

In the method of selecting a wireless microphone according to the present invention, when external noise or interference occurs, the noise level of each channel is detected, and a specific channel is selected according to the magnitude of the detected noise level. To be done.

Therefore, when external noise or interference occurs, a channel free of external noise or interference is selected without performing a selection operation of a frequency used corresponding to the channel.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals.

3 to 4 show the configurations of a wireless microphone and a receiver according to an embodiment of the method for selecting a wireless microphone according to the present invention. As shown in these figures, on the wireless microphone side, the microphone 1
When the audio signal taken in from is amplified by the amplifier 2, it is modulated by the oscillation frequency corresponding to the transmission channel by the VCO 3, further amplified by the high frequency amplifier 4, and then transmitted from the antenna 5. The setting of the transmission frequency corresponding to the transmission channel in the PLL circuit is
According to the selection of the frequency selection switch 8, the CPU 7 is PLL
This is done by supplying control data to 6.

The data input section 9 is adapted to receive channel data from the receiver side, which will be described later, using infrared rays as a carrier, and the CPU 7 supplies control data to the PLL 6 based on the channel data. The carrier of the channel data is not limited to infrared rays, but weak radio waves may be used.

On the other hand, on the receiver side which receives the high frequency signal transmitted from the wireless microphone, the high frequency signal taken in from the antenna 10 is amplified by the high frequency amplifier 11 and converted to an intermediate frequency by the mixer 12, and then by the intermediate amplifier 13. Once amplified, the detector 14
It is demodulated by being detected by. Mixer 1
2 includes a PLL including a local oscillator 15 and a PLL 16.
The set frequency corresponding to the reception channel from the circuit is taken in, and the intermediate frequency (10.7 MHz) is obtained by mixing the high frequency output from the high frequency amplifier 11 and the oscillation frequency from the local oscillator 15.
The CPU 17 outputs control data to the PLL 16 in response to the selection of the frequency selection switch 18.

The audio signal which is the detection output of the detector 14 is converted into a digital signal by the A / D converter 19 and then taken into the CPU 17. CPU1
Reference numeral 7 compares the noise level included in the converted data from the A / D converter 19 with a reference level, and when the noise level is higher than the reference level, automatically scans an empty channel to determine the noise level. Select the least receive channel. At this time, the CPU 17 sends the selected channel data to the display 20, so that the display 20 displays the selected reception channel. Further, the CPU 17 sends out the channel data selected via the data output section, using infrared rays as a carrier.

Next, a method of selecting a wireless microphone having such a configuration will be described with reference to FIG. In the flow described below, the usable channel between the wireless microphone and the receiver is, for example, 30 channels.

First, when reception is started on the receiver side,
The CPU 17 takes in the audio signal which is the detection output of the detector 14 converted by the A / D converter 19.

At this time, the CPU 17 causes the A / D converter 19
The noise level included in the converted data from is compared with the reference level. If the noise level is higher than the reference level, the scan operation is performed from the first channel with n = 1 (steps 501 and 502).

In the scan operation of the first channel, similarly to the above, the CPU 17 compares the noise level included in the converted data from the A / D converter 19 with the reference level, and the result of this comparison is stored in the internal memory of the CPU 17 ( (Not shown), and n = n + 1 is set, and the scan operation of the second channel is started (steps 503 and 50).
4).

When the scan operation for channels 1 to 30 is completed in this way (step 50)
5) The noise levels of the respective channels stored in the internal memory are compared. That is, the noise level data of the first channel is minimized, and MIN = data 1 is set to compare with the noise level data of the second channel (steps 506 to 508). When the noise level of the second channel is lower than the noise level of the first channel, the data of the noise level of the second channel is minimized, and the noise level of the second channel is compared with the noise level of the third channel. I do. If the noise level of the second channel is higher than the noise level of the first channel, the noise level of the first channel is set to the minimum and the noise level of the first channel is compared with the noise level of the third channel. I do. In this way, the channel with the lowest noise level is always compared with the channel with the lowest noise level for all 30 channels (steps 509 to 511).

When the minimum noise level is judged by such noise level comparison, the judged channel is displayed on the display 20 (step 5).
12). At the same time, the CPU 17 outputs a signal corresponding to MIN to the data output unit 21, so that the selected channel data is sent from the data output unit 21 to the wireless microphone side (step 5).
13).

As a result, when the data input section 9 takes in the channel data on the wireless microphone side, the C
The PU 7 recognizes the channel data and outputs the control data to the PLL 6, whereby the transmission frequency of the VCO 3 is adjusted to the selected reception channel on the receiver side.

As described above, in this embodiment, when the noise level of any channel exceeds the reference level, the CPU 17 on the receiver side scans all the channels and selects the one having the lowest noise level. At the same time, the selected channel data is sent to the wireless microphone side via infrared rays so that the transmission channel on the wireless microphone side matches the receiving channel on the receiver side.

Therefore, even if external noise or interference occurs in the channel currently in use,
It is not necessary to select a channel with less external noise or interference by operating the frequency selection switch 18 on the receiver side, and at the same time, it is not necessary to select a transmission channel by operating the frequency selection switch 8 on the wireless microphone side. Becomes

In the present embodiment, if external noise or interference occurs in the channel currently in use, all channels (described as 30 channels in the embodiment) are caused to perform the scanning operation, The case of selecting the channel with the lowest noise level has been described, but the present invention is not limited to this example. For example, the scan operation is started from one channel, and the scan operation is performed when a channel whose noise level is lower than the reference level is detected. It may be stopped. In this case, since the number of channels to be scanned is small, the operation of selecting a channel with a low noise level can be accelerated.

When external noise, interference, etc. occur, the scanning is not limited to the above example, but the scanning is performed at random, and the scanning operation is stopped at the time when the channel whose noise level is lower than the reference level is detected. However, in this case, it is not necessary to sequentially scan the adjacent channels, so that the detection of the channels lower than the reference level is speeded up, and the selection operation of the channel with a low noise level is further speeded up.

In this embodiment, the case where the detected output audio signal is used for the noise level comparison has been described, but the present invention is not limited to this example, and for example, an intermediate frequency (IF) signal may be used. In this case, the direct current (DC) level of the intermediate frequency (IF) signal is A / D converted and compared.

[0029]

As described above, according to the wireless microphone tuning method of the present invention, when external noise or interference occurs, the noise level of each channel is detected, and the detected noise level is detected. A specific channel is selected according to the size of.

Therefore, when external noise or interference occurs, a channel with no external noise or interference is selected without selecting the operating frequency corresponding to the channel. Can be done automatically.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a conventional wireless microphone.

FIG. 2 is a block diagram showing a configuration example of a conventional receiver.

FIG. 3 is a block diagram showing a wireless microphone according to an embodiment of a wireless microphone tuning method of the present invention.

FIG. 4 is a block diagram showing a receiver according to an embodiment of a wireless microphone tuning method of the present invention.

5 is a flow chart for explaining a channel selection operation in the receiver of FIG.

[Explanation of symbols]

 1 Microphone 2 Amplifier 3 VCO 4 High Frequency Amplifier 6,16 PLL 5 Antenna 7,17 CPU 9 Data Input Section 10 Antenna 11 High Frequency Amplifier 12 Mixer 13 Intermediate Amplifier 14 Detector 15 Local Oscillator 18 Frequency Selector Switch 19 A / D Converter 20 Display 21 Data output section

Claims (1)

[Claims] 1. A wireless microphone tuning method for selecting a channel between a wireless microphone and a receiver, wherein a noise level for each channel is detected, and a specific noise level is detected according to the detected noise level. A method for selecting a wireless microphone, which is characterized by selecting a channel.